Review the setup for the payment terms on the order. Advanced Payment terms are defined in P00145. If no rule is defined for the payment term, check to see if the Installments Present box is checked. If so, take the Form exit for Installments and check to see if a rule is defined for the installments. To see if the rule depends on a Work Day Calendar, use Program P00146. If the payment term assigned to the order is dependent on a work day calendar, ensure the calendar is setup.